Electron-tube oscillator



Dec. 15, 1925. 1,565,416

L. W. CHUBB ELECTRON TUBE OSCILLATOR Filed Feb. 14. 1921 Fig.2.

WITNESSE Z INVENTOR 4' lenlglflarr/kyfalzb'lzllbb.

Patented Dec. 15,, 1925.

um'rsn STATES PATENT. OFFICE.

LEWIS WARRINGTON CHUBIB, or nnenwoon PARK, PENNSYLVANIA, AssIGNoR T0WESTINGHOUSE ELECTRIC 6; MANUFACTURING. COMPANY, A conPonA'rIoN 011'PENNSYLVANIA.

ELECTRON-TUBE OSCILLATOR.

Application filed February 14, 1921. Serial No. 444,636.

have invented a new-and useful Improve;-

ment in Electron-Tube Oscillators, of which the following isa-specification.

My invention relates to wireless transmission systems and particularlyto vacuumtube oscillation generators employed'in connection with suchsystems.

The object of my invention is to provide an oscillation generator of theaboveindicated character thatshall be simple in construction, reliablein operation and of a higher efiiciency than has heretofore beenobtained in such tubes.

In the present type of vacuum tube em ploying a single anode. a limitingfeature in the design of the tube is the maximum operating temperatureof the anode.

As is well known, a large portion of the energy supplied to theplate-filament circuit is lost as heat at the anode. *At present, byreason of the large heat losses incurred, the maximum operatingefiiciency of the threeelectrode vacuum-tube is approximately 50%. Thismeans that practically one half the energy supplied to the vacuum tubeis lost as heat at the anode.

The maximum temperature at which the material constituting the anode maybe operated is limited first; by the melting point of the material andsecond; by the rate of evaporation of the material. 5 According to myinvention, I provide an oscillationgenerator in which a plurality ofanodes are employed to reduce the w0rkingtemperature of the individualanodes, thereby permitting a greater energy input to the vacuum tubewithout undue heating. Briefly speaking, my invention comprises aplurality of plate elements, asource of: electron emission and meansincluded in an oscillatory circuit whereby an electron stream may beselectively controlled to impinge upon predetermined groups of the plateelements to' cause the oscillations in the oscillatory circuitto besustained.

My invention may best be understoodby,

reference to the accompanying drawings, in which:

Fig. 1 is a diagrammatic viewof circuits and apparatus embodying myinvention.

Fig. 2 is a view, partially diagrammatic and partially. structural,showing my invention as applied to a wireless-transmission system.

Referring to Fig. 1, an oscillation generator 1 comprises anelectron-emitting cathode 2 and a plurality of curved anoiie elements orplates 3 and 4 which are disposed alternately around the insideperiphery of the vacuum-tube device 1 and are inclined in oppositedirections with respect to a line connecting the cathode 2 with therespective anode elements Sand 4. i The anode elements 3 and 4 areconnected in parallel relation by means of conductors 5 and 6,respectively. The hot cathode 2 may be energized by means of a battery 7through a resistor &

A high-frequency oscillatory circuit, which is connected in shuntrelation to the groups of plate elements 3 and 4, comprises a variablecapacitance 9, an inductance'coil 11 and a balance coil 12. Theinductance coil 11 is so disposed that the magnetic field therefrom istransverse to, the electro path, and the intensity of the magneticfield, at the surface of the hot cathode 2, is substantially zero. i

An electrostatic field is produced between. the hot cathode 2 and theplurality of plate elements 3 and 4 by means of a sourceof energy 13which is included in a circuit that extends from the hot cathode 2 tothe lurality of plate elements 3 and 4 throng a conductor 14, the sourceof energy 13, a balance coil 12 and the conductors 5 and 6,respectively. v

Referring to Fig. 2, the arrangement shown difiers from'that of Fig. 1by reason of the fact that the capacitance of the condenser 9 isreplaced by that of an antenna 15. In this arrangement, I have. shownthe coil 11 so di magnetic fie d that is substantially zero at thesurface of the hot cathode 2. The oscillatory circuit"includestheantenna 15, a

osed as to produce a transverse variable inductance coil 16, theinductance coil 11, the balance coil 12 and a ground lead 17.

In the operation of my invention, I utilize the well known effect of atransverse magnetic field upon the path of an electron stream. In avacuum-tube device comprising a central filament and a co-axiallymounted anode, the electrons emitted from the heated filament travel insubstantially straight lines to the surface of the anode. Uponimpressing a transverse magnetic field upon the electron path, the pathof the electrons becomes curved, the degree of curvature depending uponthe intensity of the transverse magnetic field. Thus, with asufficiently strong transverse magnetic field, the electron path may beso bent that alternate anodes will shield the remaining anodes from theelectron stream.

I have found that, by reducing the magnetic field in the spaceimmediately surrounding the cathode to substantially zero, the electronsare permitted to attain such velocity that, upon entering the magneticfield, the effect thereof is not sufficient to cause the electrons toreturn to the cathode.

In operation, upon impressing a transverse magnetic field upon a portionof the electron path, the electronspass radially outwardly from thesurface of the hot cathode until they enter the magnetic field,whereupon the path of the electron is curved to cause it to strike oneof the groups of anode elements 3 and 4. Such a path may -be indicatedby the dotted lines 18 of Fig. 1,

in which the electrons are caused to strike anodes 3. i

Upon a reversal of the magnetic field, the path of the electrons, uponentering the region of the magnetic field, is curved in the oppositedirection to cause the electrons to impinge upon the opposite group ofanode elements 4. This path is represented by the dotted lines 19 inFig. 1.

Thus, it can be'seen that, with the phase of the magnetic fieldandplate-filament cur rent adjusted properly, the direction of theplate-filament current through the balance coil may be such as toestablish and maintain an alternating current in the oscillatorycircuit.

From the foregoing description, it will be observed that the advantageof my invention resides in the provision of an'oscillation-generatorsystem in which the customary anode losses may be distributed among theplurality of anodes, thus permitting the construction of a high-powervacuum-tube device of relatively small dimensions. While I have shownonly one embodiment of my invention, it is capable of various othermodifications without departing from the spirit and scope of myinvention. I desire, therefore, that only such limitations means forestablishing an electrostatic field I between said cathode and saidanodes, whereby a space current is created in said vessel, and meansoperatively associated with said oscillatory circuit for directing thespace currenet alternately from one plurality of plate elements to theother.

2. An oscillation generator comprising an evacuated vessel. a pluralityof plate elements electrically connected, a second plurality of plateelements electrically connected to one another and arranged to alternatewith the plate elements of the first plurality, an oscillatory circuitincluding separate, serially-connected, inductance and capacitancedevices and connecting one of said pluralities to the other, a cathode,and means for establishing an electrostatic field between said cathodeand said anodes, whereby a space current is created in said vessel,certain of said serially connected devices being operatively associatedwith said evacuated vessel to modulate said space current.

3. An oscillation-generator system comprising an evacuated vessel, aplurality of plate elements connected in parallel relation, a secondplurality of plate elements also connected in parallel relation, theplates in the two groups being arranged alternately, a cathode forsupplying a space current thereto, a circuit including inductance, asecond circuit including inductance and capacitance, both circuits beingin parallel and shunted across said first and second plurality of plateelements, and means for producing an electrostatic field between saidplate elements and said cathode.

4. In a vacuum-tube device, the combination with a plurality ofjuxtaposed plate elements, of a cathode for supplying a spacecurrentstream, means for connecting alternate plate elements in parallel in twogroups, and means whereby said space-current stream may be selectivelycontrolled to impinge upon predetermiend groups of said plate elements.

5. In a vacuum-tube device, the combination with a plurality ofjuxtaposed plate elements, of a source of electron emission, anoscillatory circuit and means included in said oscillatory circuitwhereby said electron emission may be selectively controlled to impingeupon predetermined groups of sepa- Ill) rated plate elements to causesaid vacuumtube device to function as an oscillation said electronsource and means whereby said electron stream may be selectively con-'trolled to impinge successively upon predetermined groups of separatedplate elements to cause said vacuum-tube device to function as anoscillation generator.

7. In a Vacuum-tube oscillation generator,

the combination with a source of electron emission, of a plurality ofplate elements dis posed annularly thereabout, alternate plate elementsbeing connected in parallel, means for producing'an electrostatic fieldbetween said electron source and said groups of parallel connected plateelements, an oscillatory circuit including capacitance and an inductorshunted across said groups of plateelements, said inductor beingdisposed to produce a magnetic field transverse to the electron pathsand transverse to straight lines joining successive plateelements, andsaid field being of substantially zero value in a region closelyadjacent to' said electron source and of a maximum value in thesurrounding region, whereby said electron stream may be selectivelycontrolled.

8. An electrontube device comprising an evacuated'container, a pluralityof anodes and a cathode disposed within said evacuatcd container andmeans for producing a magnetic field near the anodes, saidv field beingtransverse to the plane containing said cathode and said plateelements,- and said means being so disposed that the magnetic field atthe surface of the cathode is substantially less than in the region ofsaid anodes.

upon the one or the other of saidinclined plates.

10. The combination with an electronemitting cathode, of a pair ofplates for receiving an electron stream therefrom, one of said platesbeing dlsposed at an angle .with respect to a straight line connectingsaid plate with said cathode, and means for deflecting said electronstream to cause the same to impinge more directly uponfsaid inclinedplate, the other plate being arranged in such position as to be shieldedby said inclined plate when said stream is deflected 11, The combinationwith an electronemitting cathode, of a plurality of annularly disposedplates associated therewith, alternate plates being connected inparallel, and successive plates being inclined at opposite angles withrespectto their respective radial lines, and means for deflecting saidelectron stream to cause the same to impinge more directly upon the oneor the other of said groups of parallel-connected inclined plates.

12. The combination with an electronemitting cathode, of two groups ofalternately disposed plates for receiving an electron stream therefrom,the plates of one of said groups being disposed at anangle with] respectto a straight line connecting said cathode with said platesrespectively, and means for deflecting said electron stream to cause thesame to impinge more directly upon the inclined plates of saidlast-mentioned group, the plates of the other group being arranged insuch position as to be shielded by said inclined plates when said streamis deflected.

'13. The combination with. an electronemitting cathode, of two groups ofalternately disposed plates for receiving an elecdirections with respectto a straight line connecting said cathode with said platesrespectively, and means for deflecting said electron stream to cause thesame to impinge more directly upon oneor the other of said groups ofinclined plates, the plates being so arranged that the plates of onegroup are shielded by the'plates of the other group whensaid stream isdeflected.

14; The combination with an electronemitting cathode, of a plurality ofannularly disposed plates associated therewith, alternate plates beingconnected in parallel, and means, including an annular coil "parallel tothe plane of said. plurality of annularlv disposed plates and a smallerconcentric coil carrying current in the direction opposite to thecurrent in said annular, coil, for alternately strengthening andweakening the space current flowing tolthe two groups oparallel-connected plates.

15. The combination with an electron- Inc emitting cathode, of aplurality of annularly .1

disposed plates associated therewith, alternate plates being connectedin parallel, and

successive plates being inclined at opposite angles with respect totheir respective radial lines, annular coil parallel to the plane ofsaid plurality of annularly disposed plates and as smaller concentriccoil carrying. current in the direction opposite to the current in saidannular coil, for alternately strengthening and weakening the spacecurrent flowing to the two groups of parallel-con nected plates. 1

16. The combination with an electronand means. including an movingtoward elements disposed latively weak near said ,electron source,

tron streamto cause 10 more directl upon ceiving an electron streamtherefrom, said plates being so disposed that each protects at least apart I the protecting plate, a tuned oscillation circuit seriallyassociated with said plates, and means "responsive to said oscillationcircuit for deflecting said electhe same to impinge" the one or theother of said incline plates." v 1.7. In a vacuum-tube oscillation generator, the combination with a source, of electron emission,

annularly thereabout, alternate plate elements being connected inparallelfand succesive plates being inclined at opposite angles withrespect to their re- 'spective radial lines,-a tuned oscillation circuitseriallyv associated with said plates, and means responsive to saidosclillation circuit for producing a transverse magnetic field which isrelatively strong in the annular, re'gionof said plate .elements andrewhereby said electron stream maybe alternately deflected to impingemore directly inclined plates. 7 g

18.- In a vacuum-tube oscillation generator, the combination with asource of electron emission, of a plurality of plate ele ments disposedannularly thereabout, alternate plate elements being connected inannular coilparallel, and successive plates being inclined at oppositeangles with respect to their respective circuit shunted across saidgroups of parallel-connected plate elements, said circuit including aninductor and a co denser, a coil also shunted across s'ai plateelements, and means associated with said coil for causing anelectrostatic field .between said plurality of plate elements and saidcathode, said inductor comprising an parallel to the plane of said ofthe other from electrons nected plates.

of a plurality of plate 7 annulus.

upon the one 'or the other of said groups of corresponding members ofthe several radial lines, an oscillatory readers plurality of annularlydisposed plates and I a smaller concentric coil carrying current in thedirection opposite to thecurrent in said annular coil for alternatelystrengthening and weakening the space current flowing to the two 19. Ina device of the class described, a

disk-sha ed evacuated vessel means for 5 v u producing a space currenttherein, and

means adjacent the faces thereof for producing a field therein forcontrolling said space current. i

' 20. In a space-current device, a plurality in pairs, each pairconverging In a space-current device, a plurality of electrodes arrangedin an annular row in pairs, each pair converging inwardly and; a sourceoi electrons Within the 22. In a space-current devicc, a plurality ofelectrodes arranged in an annular row in pairs, each'pair converginginwardly and a source of electrons within the annulus,correspondingfmembers of the several pairsbeing electrically-connected.

'23. Data space-current device, a plurality of electrodes arranged in anannular row in pairs, each a source of electrons Within the annulus,pairs being electrically connected, and meansv or directing theelectrons against the faces of theelectrodes away from the other membera magnetic field pro-- gressive'ly' changing in intensity from the .llntestimony whereof, l have hereunto subsribed my name this 8th day ofFebruary, 1921.. l

groups of parallel-conof electrodes arranged in an annular row inwardly.v

pair converging inwardly,

middle toward the periphery of the cross-' section thereof. 1

nnwrs wana'rner-on-on;

